there is something wrong in what u have written........ first of all
log(a*b) = log(a) + log(b)...what u have used is log(a+b) = log(a) * log(b)..even after that u have written something wrong...check it once more....
anyway u dont need to use that.....use the basic definition of logs.........
if ln(a) = b
=> e^b = a